With help from the U.S. space program, California agencies are pinpointing major methane hot spots, most of which are not connected to oil and natural gas operations, according to Southern California Gas Co. (SoCalGas).
The Environmental Defense Fund (EDF), which has championed comprehensive methane tracking and remediation programs, said the National Aeronautics and Space Administration (NASA) study was providing "the most clear-eyed assessment" to date of California's largest sources of methane emissions.
According to the California Air Resources Board (CARB), 80% of the emissions come from agriculture and waste industries, which the NASA effort affirmed.
"Of all the greenhouse gas (GHG) emissions in California, natural gas distribution and transmission pipelines represent just 0.5%," a SoCalGas spokesperson told NGI.
That does not include the methane spewed by the prolonged storage well leak in late 2015 and early 2016 by Sempra Energy’s Aliso Canyon underground storage facility, which is now operating on a partial basis.
EDF's Tim O'Connor said similar studies in other regions of the country have stressed the need to identify "super emitters.” The latest CARB study "suggests the same is likely occurring in California," although the actual figures on methane emissions will not be released until the second phase of the project next year.
"Many times these super emitters occur randomly, such as when a major piece of equipment breaks and releases a large amount of pollution,” like Aliso Canyon, O’Connor said.
The U.S. oil and gas sector is the largest industrial source of methane emissions, but he acknowledged that in California that isn't the case, given the state's rules against leaks and venting.
As the NASA study verified, he said, “animal waste and landfills are responsible for much of the state's methane emissions and need to be addressed.”
SoCalGas is supporting new technologies to reduce methane emissions, its spokesperson said.
Among other things, the gas utility is using fiber optic cables and "point" sensors to detect leaks and third-party damage to pipelines; infrared cameras to check for leaks after new pipelines are installed; drones and other aerial survey methods to spot emissions; and advanced algorithms in smart meter systems to identify unusual levels of gas consumption in homes and business that could indicate a leak.
In addition, SoCalGas recently reported on the results of a program for capturing and reusing methane during ongoing pipeline replacement projects. The utility has captured about 1.2 MMcf since the program began a year ago.